Open Forum Infectious Diseases MAJOR ARTICLE
High Incidence of Invasive Group A Streptococcal Infections in Remote Indigenous Communities in Northwestern Ontario, Canada Natalie Bocking,1 Cai-lei Matsumoto,1 Kassandra Loewen,2 Sarah Teatero,3 Alex Marchand-Austin,3 Janet Gordon,1 Nahuel Fittipaldi,3,4 and Allison McGeer4 1
Sioux Lookout First Nations Health Authority, Canada; 2Anishinaabe Bimaadiziwin Research Program, Sioux Lookout, Canada; 3Public Health Ontario, Toronto, Canada; 4Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Canada
Background. Worldwide, indigenous populations appear to be at increased risk for invasive group A streptococcal (iGAS) infections. Although there is empirical evidence that the burden of iGAS disease is significant among remote First Nations communities in Northwestern Ontario, Canada, the epidemiology of iGAS infections in the area remains poorly characterized. Methods. Individuals that met case definition for iGAS disease and whose laboratory specimens were processed by Meno Ya Win Health Centre in Sioux Lookout, Canada or who were reported to Thunder Bay District Health Unit, Canada were identified for the period 2009 to 2014. Case demographics, clinical severity, comorbidities, and risk factors were collected through chart review. Strain typing and antibiotic susceptibility were determined when possible. Basic descriptive statistics were calculated. Results. Sixty-five cases of iGAS disease were identified, for an annualized incidence of 56.2 per 100 000. Primary bacteremia was present in 26.2% of cases, and cellulitis was identified in 55.4% of cases. The most common comorbidities identified were diabetes (38.5%) and skin conditions (38.5%). Prevalent risk factors included alcohol dependence (25%). Fourteen different emm types were identified among 42 isolates, with the most common being emm114 (17.4%), emm11 (15.2%), and emm118 (13.0%). Resistance to erythromycin and clindamycin was found in 24.6% of isolates. Conclusions. Rural and remote First Nations communities in Northwestern Ontario experience iGAS infections at a rate 10 times the provincial and national average. Compared with other North American series, a lower proportion of isolates causing infection were of emm types included in candidate GAS vaccines. Keywords. health equity; indigenous health; invasive group A Streptococcus. β-hemolytic group A Streptococcus (GAS) (also known as Streptococcus pyogenes) is a Gram-positive bacteria that causes a range of human illness and contributes to significant morbidity and mortality worldwide. Severe manifestations of invasive GAS include streptococcal toxic shock syndrome and necrotizing fasciitis [1]. High rates of invasive bacterial diseases, including invasive GAS (iGAS) disease, are frequently reported among indigenous populations in different countries, including Canada, the United States, Australia, and New Zealand [2–5]. A recent publication by the Public Health Agency of Canada from the International Circumpolar Surveillance system reported a rate of iGAS among indigenous peoples in Northern Canada approximately 2.5-fold higher than that of other Canadians [2]. No other peer-reviewed publications have characterized the Received 18 August 2016; editorial decision 7 November 2016; accepted 15 November 2016. Correspondence: N. Bocking, MD, MIPH, 3rd Floor - 54 Front Street, P.O. Box 1300, Sioux Lookout, Ontario, P8T 1B8, Canada ([email protected]). Open Forum Infectious Diseases® © The Author 2016. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (http://creativecommons.org/licenses/ by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact [email protected]. DOI: 10.1093/ofid/ofw243
incidence of iGAS among First Nations, Inuit or Metis (collectively referred to as the indigenous population of Canada). Northwestern Ontario, Canada, is home to 26 remote on-reserve First Nations communities, comprising approximately 22 000 people (approximately 12% of registered First Nations in Ontario), who occupy a geographic area the size of France. Primary care, acute care, and public health services are fragmented and complicated by historical and political jurisdictional barriers. Sioux Lookout Meno Ya Win Health Centre (SLMHC) is the primary referral hospital for all 26 communities; however, critically ill patients may be transferred directly from their home community to tertiary centers in Thunder Bay, Ontario or Winnipeg, Manitoba. The First Nations and Inuit Health Branch of Health Canada is primarily responsible for surveillance and communicable disease control for on-reserve First Nations in Canada. Recent publications have reported high rates of invasive bacterial diseases among remote on-reserve First Nations in Northwestern Ontario [6, 7]. We hypothesized that the burden of illness related to iGAS infections is particularly high in this region. METHODS
All GAS-positive cultures processed by SLMHC between January 1, 2009 and December 31, 2014 were extracted from Invasive Group A Strep in Northern Ontario • OFID • 1
Sanger sequencing using previously described primers and conditions [11]. Data were stored within Excel (Microsoft Office 2010; Microsoft, Redmond, WA) and analyzed using SPSS version 21 (IBM, Armank, NY). Basic descriptive statistics were completed with confidence intervals (CIs) where appropriate. Denominator data for the 26 communities were obtained from First Nations Inuit Health Branch, extracted from the Indian Registry System. Overall incidence was determined from an average of the crude rates each year and calculated per 100 000 population. Ethics approval was obtained through the SLMHC Research Review and Ethics Committee as well as the Research Ethics Board from the University of Toronto, Canada. RESULTS
Overall, 6674 specimens processed between 2009 and 2014 yielded GAS, and 65 cases of iGAS disease were identified. The number of cases per year ranged from 9 to 18. The annualized incidence of iGAS was 56.2 per 100 000 (95% CI, 35.4–76.9). The mean age of cases was 40 years, with a range of
High Incidence of Invasive Group A Streptococcal Infections in Remote Indigenous Communities in Northwestern Ontario, Canada Natalie Bocking,1 Cai-lei Matsumoto,1 Kassandra Loewen,2 Sarah Teatero,3 Alex Marchand-Austin,3 Janet Gordon,1 Nahuel Fittipaldi,3,4 and Allison McGeer4 1
Sioux Lookout First Nations Health Authority, Canada; 2Anishinaabe Bimaadiziwin Research Program, Sioux Lookout, Canada; 3Public Health Ontario, Toronto, Canada; 4Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Canada
Background. Worldwide, indigenous populations appear to be at increased risk for invasive group A streptococcal (iGAS) infections. Although there is empirical evidence that the burden of iGAS disease is significant among remote First Nations communities in Northwestern Ontario, Canada, the epidemiology of iGAS infections in the area remains poorly characterized. Methods. Individuals that met case definition for iGAS disease and whose laboratory specimens were processed by Meno Ya Win Health Centre in Sioux Lookout, Canada or who were reported to Thunder Bay District Health Unit, Canada were identified for the period 2009 to 2014. Case demographics, clinical severity, comorbidities, and risk factors were collected through chart review. Strain typing and antibiotic susceptibility were determined when possible. Basic descriptive statistics were calculated. Results. Sixty-five cases of iGAS disease were identified, for an annualized incidence of 56.2 per 100 000. Primary bacteremia was present in 26.2% of cases, and cellulitis was identified in 55.4% of cases. The most common comorbidities identified were diabetes (38.5%) and skin conditions (38.5%). Prevalent risk factors included alcohol dependence (25%). Fourteen different emm types were identified among 42 isolates, with the most common being emm114 (17.4%), emm11 (15.2%), and emm118 (13.0%). Resistance to erythromycin and clindamycin was found in 24.6% of isolates. Conclusions. Rural and remote First Nations communities in Northwestern Ontario experience iGAS infections at a rate 10 times the provincial and national average. Compared with other North American series, a lower proportion of isolates causing infection were of emm types included in candidate GAS vaccines. Keywords. health equity; indigenous health; invasive group A Streptococcus. β-hemolytic group A Streptococcus (GAS) (also known as Streptococcus pyogenes) is a Gram-positive bacteria that causes a range of human illness and contributes to significant morbidity and mortality worldwide. Severe manifestations of invasive GAS include streptococcal toxic shock syndrome and necrotizing fasciitis [1]. High rates of invasive bacterial diseases, including invasive GAS (iGAS) disease, are frequently reported among indigenous populations in different countries, including Canada, the United States, Australia, and New Zealand [2–5]. A recent publication by the Public Health Agency of Canada from the International Circumpolar Surveillance system reported a rate of iGAS among indigenous peoples in Northern Canada approximately 2.5-fold higher than that of other Canadians [2]. No other peer-reviewed publications have characterized the Received 18 August 2016; editorial decision 7 November 2016; accepted 15 November 2016. Correspondence: N. Bocking, MD, MIPH, 3rd Floor - 54 Front Street, P.O. Box 1300, Sioux Lookout, Ontario, P8T 1B8, Canada ([email protected]). Open Forum Infectious Diseases® © The Author 2016. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (http://creativecommons.org/licenses/ by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact [email protected]. DOI: 10.1093/ofid/ofw243
incidence of iGAS among First Nations, Inuit or Metis (collectively referred to as the indigenous population of Canada). Northwestern Ontario, Canada, is home to 26 remote on-reserve First Nations communities, comprising approximately 22 000 people (approximately 12% of registered First Nations in Ontario), who occupy a geographic area the size of France. Primary care, acute care, and public health services are fragmented and complicated by historical and political jurisdictional barriers. Sioux Lookout Meno Ya Win Health Centre (SLMHC) is the primary referral hospital for all 26 communities; however, critically ill patients may be transferred directly from their home community to tertiary centers in Thunder Bay, Ontario or Winnipeg, Manitoba. The First Nations and Inuit Health Branch of Health Canada is primarily responsible for surveillance and communicable disease control for on-reserve First Nations in Canada. Recent publications have reported high rates of invasive bacterial diseases among remote on-reserve First Nations in Northwestern Ontario [6, 7]. We hypothesized that the burden of illness related to iGAS infections is particularly high in this region. METHODS
All GAS-positive cultures processed by SLMHC between January 1, 2009 and December 31, 2014 were extracted from Invasive Group A Strep in Northern Ontario • OFID • 1
Sanger sequencing using previously described primers and conditions [11]. Data were stored within Excel (Microsoft Office 2010; Microsoft, Redmond, WA) and analyzed using SPSS version 21 (IBM, Armank, NY). Basic descriptive statistics were completed with confidence intervals (CIs) where appropriate. Denominator data for the 26 communities were obtained from First Nations Inuit Health Branch, extracted from the Indian Registry System. Overall incidence was determined from an average of the crude rates each year and calculated per 100 000 population. Ethics approval was obtained through the SLMHC Research Review and Ethics Committee as well as the Research Ethics Board from the University of Toronto, Canada. RESULTS
Overall, 6674 specimens processed between 2009 and 2014 yielded GAS, and 65 cases of iGAS disease were identified. The number of cases per year ranged from 9 to 18. The annualized incidence of iGAS was 56.2 per 100 000 (95% CI, 35.4–76.9). The mean age of cases was 40 years, with a range of
